The present invention relates generally to methods and apparatus utilized for winding coils that ultimately are used as the excitation windings of electric motors. More specifically, it relates to apparatus known as a flyer in the art and utilized for guiding and wrapping wire about a coil form means.
The above referenced Brown applications describe in substantial detail various problems encountered in winding applications. More specifically, the Brown applications discuss stabilization of wire fed to a coil form in order to reduce (if not eliminate) wire flutter, undesired crossover of turns from one coil form stage to another; and to problems associated with the "lay" of wire on a coil form.
The present invention also is concerned with the desirability of obtaining more reliable "lay" or positioning of wire on coil forms and the avoidance of undesirable wire flutter and coil form wire "crossover". The present invention is also concerned with providing improved methods and apparatus that permit rapid "fine-tuning" of winding equipment, and to permit rapid optimization of such equipment for different wire sizes, different wire or insulation materials, different stack height settings of the coil forms, and so forth.
With modern high-speed coil winding equipment for the electric motor industry, a flyer typically spins in a circular path about a multi-stage coil form and thereby generates a coil group comprising two or more coils that each comprise a plurality of turns of wire. The forms typically are made of two or more separate pieces so that they may be adjustably set to produce coil groups for motors of different axial lengths or lamination stack heights. In most cases, turns produced on the forms are oblong in shape.
In typical applications, the flyer rotates at speeds of anywhere from 1200 to 3000 rpm and the circular rotation of the flyer arm about a non-circular coil form causes extreme fluctuations (i.e. sudden and drastic changes) in the required feed rate of the wire being wrapped about the form. Such drastic fluctuations in wire feed rates cause the wire being wound on the form to be subjected, intermittently and alternately, to very high and very low tensile forces. In the absence of tension, the inertia of the wire may cause it to whip up and down or sideways and to tend to flutter between the coil form and the flyer.
As pointed out in the above-referenced Brown applications, if the flutter of wire is sufficient in magnitude it can actually cause a wire strand to be positioned on a coil form stage other than the stage intended; or it can cause a wire strand to cross over a previously generated strand and interfere with the proper movement of, or removal of, wire turns along the coil form. These problems can become particularly objectionable in the case of "shedder" or wind and shed winding equipment.
The above-referenced Brown application Ser. No. 201,220, now U.S. Pat. No. 4,387,745, filed as a continuation-in-part of application Ser. No. 114,880 discloses the use of a flyer having the nozzle thereof pointed at a fixed angle "backwards" during the winding process. In addition, that same application shows and describes, among other things, a fabricated flyer arm that permits wire to be thrown outwardly away from carbide wire guides or pulled up against such guides during a winding operation.
It would be desirable to improve the various techniques and procedures taught in the just-mentioned Brown application, and to provide still additional features.
It is, accordingly, an object of the present invention to provide a new and improved method of winding coils for electric motors and apparatus for putting such method into effect.
It is another and more specific object of the present invention to provide new and improved winding methods and flyer mechanisms which permit moving wire segments (extending between a coil form assembly and a flyer) to control the attitude of the flyer nozzle with respect to the coil form assembly, so that the flyer nozzle is virtually continuously directed along a line tangent to the moving point or points about the coil form assembly that the moving wire segment is contacting, with the ultimate result that the wire segment passing from the flyer nozzle is neither bent nor deflected by the nozzle itself.
It is still another object of the present invention to provide a new and improved winding method and flyer mechanism wherein centrifugal forces are utilized to apply a tensioning force to moving wire segments extending between a coil form and a flyer nozzle, and yet wherein centrifugal forces utilized to establish an accumulator loop of wire are restrained from throwing such accumulator or loop of wire outwardly into interfering relation with other parts of the winding equipment.
It is a further and more specific object of the present invention to provide new and improved methods and flyer mechanisms capable of carrying out the last stated object, and which also maximize the tensioning effect of the centrifugally generated accumulator loop of wire by providing a free floating flyer nozzle.
It is yet a further object of the present invention to provide an improved winding method and flyer mechanism such that reduced amounts of tension are applied to the wire in virtually all parts of the winding equipment until the wire is in close proximity to the flyer nozzle, and such that only then is more tension applied, in order to improve the wire handling capabilities of the winding equipment and improve and facilitate set up of such equipment for handling wires of different materials, different enamel coatings, and different sizes, and when making coils for stators of different stack heights.
It is a still further object of the present invention to provide new and improved winding methods and flyer mechanisms that facilitate the production of coils for electric motors by means that are conveniently and easily adjustable for purposes of optimizing the winding of coils for electric motors.